The present invention relates to a device for opening and closing a vessel containing a metal in the liquid state.
Before proceeding with pouring a metal or an alloy in order to mold it, one skilled in metallurgy knows that various stages first must be passed, from smelting the alloy through treatments for purifying the metal, and possibly transporting it to the pouring site.
All of these operations are done while the products are in the liquid state and accordingly require vessels such as melting, holding and treatment furnaces, or treatment or transport ladles for containing them.
Before being able to recover the contents of these vessels at the moment of pouring, for example, or any other transfer operation, recourse may be made to one of the following provisions: either to tilt the vessel, or to equip it with a plunger tube and exert a gas pressure on the surface of the metal, or to provide it with a pouring opening at its base, to which a sealing system such as a stopper or plug is adapted.
It is this last type of provision that the present applicant addresses in the instant application.
Generally, the opening that is made at the bottom of the vessel has the form of a truncated cone, with its wide base disposed toward the outside and its axis perpendicular to the lateral wall of the vessel.
The sealing stopper or plug, also of frustoconical shape, which in the prior art is solid with a lever, is engaged in into this opening. This lever is fixed at a point located in a vertical plane that passes through the longitudinal axis of the stopper and is moved by a rotational movement about this point, so that the stopper can be disengaged from the orifice to open the vessel or contrarily made to engage the orifice of the vessel to close it.
However, under these conditions, the stopper describes a circle, and its axis cannot remain parallel to the axis of the opening, which is horizontal. As a result, when a vessel that still contains metal is opened or closed, the stopper collides with the metal jet in an oblique rather than tangential direction, which causes spattering of metal; moreover, the end of the stopper has a tendency to rub against the walls of the opening, which slows down the opening or closing, and increases the period of time during which the spattering can be produced.
Accordingly, such a system entails risks to the safety of the workers. This is why applicant has sought and discovered a system with which these disadvantages can be overcome.